When you create something like a logo, button or background slice, why wouldn’t you just create the image to be used on the web page at the same time instead of creating the logo, button, etc, in the PSD , then later slicing it up into images for the web and then using it?

Umm…can you rephrase that please? Not sure I really understand what you’re trying to ask.

You don’t know how the final design will be until you need to make it all from scratch usually in Photoshop..and for that you need to have all the design elements together to see how they fit, modify if needed and so on.

Maybe I understood it incorrectly, but you asked why we don’t design items separately?

Your question is quite unclear but from my understanding, you mean why not just save it as a huge image that has all the text/graphics?

Uhm, that would be ridiculously stupid? First of all, it would take forever to load. Second of all, it would be a pain in the ass to modify it. Third of all, how would you be able to click on anything? There are dozens of reasons why. Feel free to ask if you want me to list them all; I can think of plenty!

I think he’s asking why designers don’t just create the individual elements on-the-fly, such as buttons, logos, etc., but instead design a full ‘mockup’ for the entire site, and then go back later and slice it up.

I’d say the reason for that is because it’s much easier (and faster) to layout a site in Photoshop, as opposed to doing it directly in HTML . Additionally, it allows the author to get a better feel/sense for the design as a whole, and make sure all of the elements work together design- and usability-wise. And finally, it’s helpful to be able to give a mockup to the site’s client to review, and much easier to make changes in the design stage through Photoshop.